Places We Protect

Mary Macdonald Preserve at Horseshoe Harbor


Water between two large rock formations, covered in lichen and other plants, along the shore of Lake Superior in the Keweenaw Peninsula of Michigan.
Horseshoe Harbor Sunrise hits the bedrock at Mary Macdonald Preserve at Horseshoe Harbor. © TNC

Since it was originally established in 1982, the Mary Macdonald Preserve has grown to encompass 1,200 acres, including five miles of Lake Superior shoreline.



At the tip of Michigan’s Upper Peninsula, stunted shrubs and trees cling to ancient bedrock created by Lake Superior’s fierce winds. Since it was originally established in 1982, the Mary Macdonald Preserve has grown to encompass 1,200 acres, including five miles of Lake Superior shoreline. While the rugged bedrock beach here supports only the toughest of plants such as lichen, the preserve is home to 11 threatened or rare species.

Along the shoreline, a rocky ridge creates a barrier for inland species and slower-growing plants. Just inland from the rock beaches, forest thrives in this cool, moist climate. Balsam fir, white cedar, white spruce and white birch provide habitat for the black bear, snowshoe hare, peregrine falcon, ruffed grouse, golden-crown kinglet, black-throated green warbler and yellow-rumped warbler. 



Pets are not permitted. Please refrain from climbing on rock formations.


Hiking, snowshoeing, birdwatching, swimming and deer hunting (by permit)


1,261 acres

Explore our work in this region

TNC's Work in the Keweenaw

Mary Macdonald Preserve is located in the Keweenaw Peninsula, an area TNC has been active in for decades. The Keweenaw has globally significant opportunities for nature-based carbon solutions and land and water protection, all contributing to the health of one of the world’s largest freshwater systems, the Great Lakes.

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A common loon flaps its wings in the water.
A green forest of trees in Michigan's Keweenaw Peninsula.
A mink frog rests in the shallow water at Mary Macdonald Preserve at Horseshoe Harbor in the Keweenaw Peninsula.
Water from Lake Superior splashes against rocks in the Keweenaw.
Aerial view of the peninsula, showing vast forests and blue water crashing on the shore.

Exploring the Preserve

The activities below will help you explore the preserve and enhance your connection with nature—from the comfort of your home or while onsite.

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    Audio Tour

    Our guided audio tour includes stories, fun facts, historical notes, and natural sounds to help deepen your connection to the Mary Macdonald Preserve. You can access the tour from the comfort of your home or onsite as you hike. Learn More

  • A person crouches down to examine green plant life while on a hike at Nan Weston Nature Preserve in Michigan.


    Help our scientists and restoration managers keep track of the species in our nature preserves by using iNaturalist. You can record your observations, help others identify species and view other users' identifications. Learn More

  • More Ways to Explore

    We offer a variety of ways to explore including geocaching, webinars, events and volunteer opportunities. You can even request a permit to use TNC lands for scientific research! Learn More


Spotlight on the Mary Macdonald Preserve

Spotlight on Nature (3:03) The Mary Macdonald Preserve at Horseshoe Harbor, on the northern shore of the peninsula, is one of our most popular preserves with visitors.

Plan Your Visit

Frequently Asked Questions

  • This preserve is open year round. However, late summer and early fall are the best times to visit to fully enjoy the beauty of the Keweenaw Peninsula without the irritation of the biting insects that come out in the early summer. 

  • Hiking boots are recommended for walking the trails and shoreline of this preserve. If you want to visit during the early summer months bring insect repellant to protect against biting insects.

    • Hiking, skiing, and snowshoeing
    • Bird watching, nature study and photography
    • Swimming
    • Geocaching
    • Kayaks and canoes are permitted on Lake Superior. Vessels must be carried from the parking area.
    • Research projects and educational studies with approved permit
    • Hunting with a Conservancy-issued permit for whitetail deer
  • For the safety of both the habitats at this preserve and visiting guests, we ask that you please follow the rules listed below.

    • No pets
    • No rock climbing and rappelling
    • No motorized and non-motorized vehicles
    • No building of new trails
    • No hunting or trapping without a TNC-issued permit
    • No removal of plants or animals (alive or dead)
    • No removal of rocks, water or other non-organic materials
    • No camping, bonfires, fireworks or other fires
    • No firewood collecting
    • No littering
  • The Nature Conservancy allows hunting for white-tailed deer on this preserve to reduce threats too many deer can pose to the other plants and animals that live here. All hunters are required to receive a permit from TNC as well as a Michigan deer hunting license. Additionally, hunters must report any deer taken from the preserve.

  • Have questions about the preserve? Contact us at

Keep Exploring

From shifting sand dunes to granite bald mountains, explore our preserves and reserves spread across the state of Michigan.

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Find More Places We Protect

The Nature Conservancy owns nearly 1,500 preserves covering more than 2.5 million acres across all 50 states. These lands protect wildlife and natural systems, serve as living laboratories for innovative science and connect people to the natural world.

See the Complete Map

Make a Lasting Impact

You have the power to make a difference for the Great Lakes State and for our planet. Your support will help fund groundbreaking science and conservation activities that protect the lands and waters you love.